A typical inserter system comprises a document transport unit (hereinafter "conveyor") for transporting documents, a plurality of document entry devices disposed along the conveyor for ejecting documents onto the conveyor, usually an envelope module for introducing an envelope to the conveyor and inserting collations of documents into the envelope, and a controller for exercising control over the operation of these components.
As used herein: a "document" is a piece of material, such as a single sheet of paper or a piece of paper separated into a single sheet from an interconnected series of sheets, such as a computer printout; a "Document Entry Device (DED)" is a mechanism that is suitable to eject documents onto a conveyor; a "conveyor" is a mechanism that is suitable to transport documents from one DED to another DED, thus enabling the compilation of related documents into a collation of documents in an orderly manner; a "Single DED (SDED)" is a DED that is suitable to eject a single document at a time onto a conveyor; a "Multiple DED (MDED)" is a DED that is suitable to assemble more than one document as an "enclosure" and to eject the entire enclosure onto the conveyor; and a "collation" is a set of documents and/or enclosures compiled by the cooperative actions of the conveyor and the DEDs.
The proper compilation of documents and/or enclosures into collations on the conveyor requires careful synchronization by the contrioller over the ejection of documents and/or enclosures by the DEDs as well as over the movement of the conveyor. As is well known to one skilled in the art to which this invention pertains, the assembly of an enclosure by an MDED prior to its ejection onto the conveyor may necessitate stopping the conveyor in order to allow the MDED time to assemble the enclosure prior to related documents in the collation arriving at the MDED on the conveyor. After the assembly of the enclosure is completed by the MDED, the conveyor must be restarted to continue the compilation of the collation. This mode of operation is termed the "stop-start" mode.
The "stop-start" mode of operation has a number of undesirable effects on the performance of the inserter system. First and foremost, it is responsible for the majority of jams experienced by the inserter system. Second, it increases mechanical wear on all components affected by the stop-start action. Third, it necessitates more complex synchronization between the DEDs and the conveyor. Fourth, it tends to reduce the inserter system throughput.